1. Field
The following description relates to a seismic imaging technology technique for modeling a subsurface structure through waveform inversion in the Laplace domain.
2. Description of the Related Art
Technologies for imaging a subsurface structure through waveform inversion have been studied and developed. The full waveform inversion method was initially developed in the time domain to recover subsurface information. Later, this work was extended to the frequency domain. However, full waveform inversion methods have limitations due to local minima in their objective functions. Also, full waveform inversions of field data remain limited due to insufficient low-frequency information.
Recently, a Laplace-domain waveform inversion technique has been proposed to address problems associated with inversions in the frequency or time domains. See Shin, C., and Y. H. Cha, 2008, Waveform inversion in the Laplace domain: Geophysical Journal International, 173, 922-931; and Pyun, S., W. Son, and C. Shin, 2011, 3D acoustic waveform inversion in the Laplace domain using an iterative solver: Geophysical Prospecting, 59, 386-399. Also see Bae H. S., C. Shin, Y. H. Cha, Y. Choi, and D. J. Min, 2010, 2D acoustic-elastic coupled waveform inversion in the Laplace domain: Geophysical Prospecting, 58, 997-1010 and Kim, M. H., Y. Choi, Y. H. Cha, and C. Shin, 2009, 2-D frequency-domain waveform inversion of coupled acoustic-elastic media with an irregular interface: Pure and Applied Geophysics, 166, 1967-1985.
Laplace-domain waveform inversion could solve the problems of insufficient low-frequency information and local minima by using the zero-frequency component of a damped wavefield. Combining the work of Bae et al. (2010) and Kim et al. (2009) above, we have developed an inversion algorithm that can account for the effects of elastic waves in a marine environment and describe irregular submarine topography which was disclosed in Kang, S. G., H. Bae, and C. Shin, 2012, Laplace-Fourier domain waveform inversion for fluid-solid media: Pure and Applied Geophysics, 169, 2165-2179. However, the inversion can produce artifacts near the seafloor due to topography, and it requires longer streamers than required for frequency-domain inversions for the recovery of deep-water structures.